The overarching goal of this proposal is to examine the overlap in the sexual and drug co-usage networks of men who have sex with men (MSM) and to overlay information about sexual partnerships facilitated by the use of social networking applications (e.g., Grindr, Scruff, etc.) to determine the relationship between app use and network-level patterns of HIV risk behavior. Many MSM are using social media and/or smartphone applications (apps) to meet sex partners, and evidence suggests that use of these apps is associated with increased sexual risk behavior and possibly drug use, although research on the latter is scarce. Unfortunately, network- based research in this area has focused almost exclusively on sexual networks; thus, little is known about the interaction of MSM sexual- and drug-related risk networks and how network structure is influenced by the use of mobile apps. Moreover, previous studies generally have lacked necessary detail about partnerships to be able to determine the interconnectivity of relationships. Finally, the overwhelming majority of studies on MSM app use have been conducted in large urban areas, despite research indicating that similar patterns of online- and app-based sex-seeking occur among MSM in rural and mid-sized cities. The gap in knowledge is notable considering evidence suggesting that rural MSM experiencing stigma and isolation often use the Internet to find sex partners and travel to/from nearby urban areas to meet them. The proposed study will be conducted in a mid-sized city in the South in close proximity to rural Central Appalachia. The study was developed in response to the need for more integrative network-level research on app use and the drug co-usage and sexual relationships of MSM residing outside of large urban areas. Through the use of a name generator and collection of detailed demographic information about partners, the proposed study will allow inferences to be drawn about overlap in sexual and drug co-usage partnerships in a network structure representing the direct and indirect connections among all participants and their partners (i.e., a sociometric network). The network will reveal the relationship between app use and co-occurrence of drug and sexual partnerships and, through the integration of spatial data on locations of sexual encounters, will permit examination of the relationships among risk behavior, network structure, and spatial context. Identifying high-risk spatial locations and network structures will be critical in determining ho best to reach MSM using combined geo-targeted and network- driven approaches as well as app- or web-based technologies.